An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

The level that must be reached for a physical effect to begin or be noticeable.

M.E. threschold, O.E. threscold, threscwald "doorsill, point of entering."

Âstâné "threshold; a place of rest or sleeping," variant âstân; Mid.Pers. âstânak; ultimately from Proto-Iranian *ā-stānaka-, from *stā- "to stand;" cf. O.Pers./Av. sta- "to stand, stand still; set;" Av. hištaiti; Mid.Pers. êstâtan "to stand;" Mod.Pers. istâdan "to stand;" cf. Skt. sthâ- "to stand;" Gk. histemi "put, place, weigh," stasis "a standing still;" L. stare "to stand;" Lith. statau "place;" Goth. standan; PIE base *sta- "to stand."

The minimum energy necessary for the occurrence of some chemical/physical effect.

→ threshold; → energy.

The minimum energy, for an incident particle or photon, below which a particular reaction does not occur.

→ threshold; → reaction.

The minimum intensity of a signal that can be detected and recognized.

→ threshold; → signal.